Could Gnomoniopsis castaneae Be Used as a Biological Control Agent against Insect Pests?

Spiridon Mantzoukas,Konstantinos Poulas,Dimitrios Ν Avtzis,George T Tziros,Ioannis Lagogiannis,Panagiotis A Eliopoulos,Aristeidis Ntoukas

doi:10.3390/app11094066

Spiridon Mantzoukas, Konstantinos Poulas + Show 5 more

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https://doi.org/10.3390/app11094066

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Abstract

Gnomoniopsis castaneae is the cause of the chestnut brown rot but has been also regarded as an important mortality factor for the chestnut gall wasp Dryocosmus kuriphilus. The question to whether G. castaneae could serve as a natural biocontrol agent against insect pests is investigated in the present study. We used three serious insect pests as experimental model insects: Plodia interpuctella and Trogoderma granarium, which are important pests of stored products, and Myzus persicae, a cosmopolitan, serious pest of annual and perennial crop plants. Although chemical pesticides represent effective control means, they are also related to several environmental and health risks. In search for alternative pest management methods, scientific interest has been focused, inter alia, on the use of entomopathogenic fungi. While Isaria fumosorosea has long been recognized as an effective control agent against several pests, G.castaneae has been very little studied. The present study examined whether and to what extent G. castaneae and I. fumosorosea exhibit insecticidal activity against fourth-instar larvae of P. interpunctella and T. granarium and adults of M. persicae. Mortality was examined in interrelation with dosage and time exposure intervals. Both fungi exhibited pesticidal action. However, G. castaneae induced noteworthy mortality only at very high doses. In general, we concluded that G. castaneae failed to cause high insect pathogenicity at normal doses and may not be an efficient biocontrol agent compared with other entomopathogens. On the other hand, our study reiterates the pathogenic potential of I. fumosorosea. More studies are needed to further our insight into the potential of EF species as a component of IPM.

Highlights

Entomopathogenic fungi (EPF) make up a specialized group of fungi which comprise numerous genotypes [1]
The original habitat underlines the pathogenicity of EPF species [41], evaluation assays of potential isolates should not be targeted only at the original host, and at various insect pests, as it was clearly indicated by our results
G. castaneae may not be the ideal EPF candidate to select for a biological control strategy

Summary

Introduction

Entomopathogenic fungi (EPF) make up a specialized group of fungi which comprise numerous genotypes [1]. EPFs inhabit a wide range of dwellings including urban environments, meadow land, dry, and agricultural places. They demonstrate high virulence against many insects and have minimal residual effects. Insect pathogens have a biological cycle that is synchronized with that of the host and adapted to the prevailing environmental conditions [3]. Infection can be restricted by low levels of relative humidity, shortage of nutrients in the cuticle, as well as the inability to recognize the host due to the absence of contributing factors [4,5]. The degree of the infection depends on the infectivity of the fungus, the defensive resilience of the insect, and several other biological and abiotic factors [3].

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